Problem: Ishaan ate 3 slices of cake. Vanessa ate 5 slices. If Ishaan ate $\dfrac{3}{12}$ of the cake, what fraction of the cake is remaining?
Solution: If 3 slices represent $\dfrac{3}{12}$ of the cake, there must have been a total of 12 slices. $\text{fraction of cake remaining} = \dfrac{\text{number of slices remaining}}{\text{number of slices total}}$ Together they ate 8 slices, which leaves 4 out of 12 slices remaining. There is $\dfrac{4}{12}$ of the cake remaining.